Soak the wood chips for 2 hours, drain. Prepare a slow charcoal fire in a covered grill. Arrange 1/2 of the wood chips on the coals.
Combine the dry ingredients for the rub except the vinegar. Brush the brisket with the vinegar and thoroughly coat the meat with the rub. Place the brisket on the grill, fat side up, over a drip pan. Close the lid and smoke for 2 1/2 to 3 hours, adding more soaked wood chips as needed.
To make the sauce, saut� the onion and garlic in a little of the oil until soft. Add the remaining ingredients and simmer for 30 minutes.
Generously brush the brisket with the sauce a couple of times during the last 1 to 1/2 hours of cooking.
Keep the sauce warm and add additional catsup to achieve the desired consistency.
To serve, cut the brisket across the grain and serve with the sauce on the side.